@Override
Widget computeTabGroup() {
ToolItem[] items = _getItems();
if (tabItemList == null) {
int i = 0;
while (i < items.length && items[i].control == null) i++;
if (i == items.length) return super.computeTabGroup();
}
int index = indexOf(currentFocusItem);
if (index == -1) index = items.length - 1;
while (index >= 0) {
ToolItem item = items[index];
if (item.isTabGroup()) return item;
index--;
}
return super.computeTabGroup();
}
